Z. Vendroff, the prominent Soviet Jewish writer, who was 94 in January, has just published several chapters of his autobiography, according to reports from Moscow. He was said to be hale and hearty and hard at work on the remainder of the book. Vendroff was born in Russia and subsequently moved to New York, Warsaw and Moscow, where he was arrested during the Stalinist repression and sent to Siberia for six years (1948-54). Rehabilitated by the Khrushchev regime. Vendroff returned to Moscow and became the dean of Soviet Jewish writers. His collection of short stories last year was one of only six books in Yiddish published in the Soviet Union since the death of Stalin in 1953.